The input/output system relations are conveniently illustrated by the use of block diagrams, as in Fig. 3.2. Figure 3.2a is the overall system diagram showing inputs f1 and /2 and output e and Fig. 3.26 is the combined block diagram of the subsystems, showing the sort of interconnections and feedbacks that are typically encountered in real systems.
Fig. 3.2 Block diagram, (a) Complete system. (6) Detailed block diagram. = spring forces, d = damper force. ri = reaction forces.